Add npm publish action (#64)

.github/workflows/publish.yml

@@ -0,0 +1,28 @@
+name: Publish to npm
+
+on:
+  pull_request:
+    types: [closed]
+    branches:
+      - main
+      - master
+    paths:
+      - "package.json"
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    if: >
+      github.event.pull_request.merged == true &&
+      contains(github.event.pull_request.labels.*.name, 'Release')
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v3
+        with:
+          node-version: lts/*
+          registry-url: "https://registry.npmjs.org"
+      - run: npm ci
+      - run: npm run build
+      - run: npm publish --access public
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}